Antioxidants are widely used to preserve a variety of materials including food, vitamins, and pharmaceuticals. Such materials are naturally degraded by oxidants, such as oxygen radicals, present in the material or its environment. These oxidants are highly reactive and accordingly bond to and/or break down other chemicals in the material, resulting in the appearance of undesirable properties in the material. To avoid these undesirable effects, an antioxidant may be added to the material. The antioxidant has a strong affinity for oxidants and therefore provides a preferred reactant. Some such reactions may produce an undesirable by-product, but many do not. Antioxidants used for preservative purposes are selected to avoid undesirable by-products.
Foods commonly treated with antioxidants include oils, which are often used for cooking and tend to oxidize more rapidly at higher temperatures, oil-containing foods such as coffee, and dried foods. Many vitamins, including Vitamins C and E, are themselves antioxidants and therefore are rapidly degraded unless another antioxidant is provided with the vitamin. A large number of pharmaceuticals, such as synthetic estrogens, also benefit from the addition of antioxidants, especially if oxidative damage may result in a toxic by-product.
In addition to their preservative effects, many antioxidants also have physiological effects. Antioxidants are known to reduce the inflammatory response and may be used in conjunction with other drugs to treat conditions resulting from or worsened by inflammation. Additionally, it is believed that ingestion of some antioxidants, such as Vitamins C and E, helps prevent cancer and other disorders caused by oxidative damage to the body.
Accordingly, many antioxidants are available at present. These include artificial antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and tert-butyl hydroquinone (TBHQ). Vitamin E, generally used to describe a class of chemicals known as “tocopherols”, and Vitamin C, also commonly called “ascorbic acid”, are also used as antioxidants. Natural antioxidants such as tea extracts and extracts of herbs such as rosemary are also used for antioxidant purposes.